Thermostat



' (No Model.) Y

J. R. ROBERTS.

THBRMGSTAT.

No. 499,926. n Patented Jan. 31, 1893.

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JOHN R. ROBERTS, OF HOMER CITY, PENNSYLVANIA.

THERMOSTAT.

SPECIFICATION forming part of Letters Patent No. 490,926, dated January31, 1893.

Application tiled August 17, l892. Serial No. 443,312. (No model.)

To all whom it may concern:

Be it known that I, JOHN R. ROBERTS, a citizen of the United States,residing at Homer City, in the county of Indiana and State ofPennsylvania, have invented certain new and useful Improvements inThermostats; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to automatic expansion dampers, and is athermostat adapted to control a valve or register for regulating thetemperature of incubators or broeders, or for other purposes; and theobject hereof is to produce a device which will be very sensitive to.changes in temperature, no matter how great or small such changes maybe.

To this end the invention consists in a device constructed substantiallyas hereinafter more fully described and claimed, and as illustrated onthe sheet of drawings, wherein- Figure 1 is a longitudinal section of anincubator, showing my improved device in side elevation therein andconnected to open or close a Ventilating register in one end thereof.Fig. 2 is an enlarged central longitudinal section of this thermostat,showing in dotted lines how the spring may be sometimes constructed.

In the said drawings, the letter A represents a base or casing which maybe of any material that does not expand in heat or contract in cold, andof any suitable length, its sides, top, and ends being preferably opento permit the free circulation of air.

B is a strip of brass, iron, or other metal that is affected by heat andcold. This strip is fastened at its ends by the screws, bolts, or rivetsto the base A, and elevated between such ends, forming a toggle leverhaving an obtuse angle of a few degrees. On this strip near lthe centerand at one side 'of the angle is fastened by screws, bolts, or rivets Ra spring C which is of any suitable material` preferably metal-that willanswer the purposes for which it is to be used. I prefer to fastened asat R would pass above the angle of the strip and to or nearly to theother end thereof. Rising from the base or casing is a pin F to which ispivoted at Ga lever L, and the latter is pivotally connected by a rod Pwith the outer end of the spring C. Thus the point F forms thefulcrum,the spring C and rod P the power, and whatever is connected with theother end of the lever the load= hence this is a lever of the thirdclass. In :the present case I have shown the outer end of the lever asconnected by a rod P with a Ventilating register in one end of anincubator I. Still of course its uses could be other than that shown,and the manner of connecting it with the register could be differentwithout departing from the spirit of my invention.

Figs. 3 and 4 illustrate more particularly the construction of thetoggle-lever strip B in its preferred form. Heretofore such expansiblestrips have been made in toggle-lever form with the two memberspivotally connected at their meeting ends, but in the present case Iprefer to make the entire strip of one piece as shown. At its centerthis strip is provided with a transverse row of perforations c wherebythe material is slightly weakened, andit is here that the obtuse angleoccurs. Each side of this point, thestrip is preferably slightly wider,and its edges are bent down as at b so as to give the members of thetoggle a certain rigidity; because if they were permitted to bend'orspring, the rise and fall of the angle could not be employed as abovedescribed. Near the outer ends of the members, they are bent up as at cto form a slight shoulder, and then out again as at d to form a footwhich is secured as by nails or screws e to transverse blocks f IOO itmay bend at this point as the toggle rises and falls. While I do notconfine myself to this precise manner of constructing the strip, Iconsider it advisable that it be adopted.

When the temperature in the incubator rises, the metallic strip B isexpanded. As its ends are fast, its center must rise, and this carriesthe spring C up with it. In so doing, the inner end of the spring israised for a short distance, whereas its outer end is moved through agreater path. It' the angle Q is present in the spring (as it is in mypreferred form) it will be obvious that the spring will possess acertain yielding power, and even without this 'anglesome of suchyielding will be present. As it rises, the outer end of the springforces up the rod P which connects the spring and lever and causes thelong arm of the latter to rise and thereby to open the register D or todo whatever other work may be desired of it. When the strip B is actedupon by the cold, just the opposite action will take place: that is, thestrip will contract and thus draw down the spring to move the register Din the opposite direction. In case the register sticks in place or someof the connections becomebroken or clogged, it will be seen that thespring will yield and thus prevent breakage of this thermostat. Theregister may be moved by hand at any time, since the spring will yieldto permit; or the register may be locked in open or closed position, andthe yielding of the spring will permit the strip to expand and contractwithout breaking the device.

I do not limit myself to the exact shapes, sizes, and proportions ofparts, and it will be obvious that the device may be put to many otheruses than that herein described and shown. For instance, it may beemployed to regulate the dampers in tlues or heating pipes for steam orhot air, or to set valves in tubes, or in other places where a mean andeven temperature is desired.

What is claimed as new isl. The herein described thermostat, the sameconsisting of a casing, a strip of expansible material secured at itsends to said casing and forming an angle between them, a lever pivotedto the casing, a spring extending over said angle and secured at one endto the strip near its angle, and a rod between its other end and thelever, as and for the purpose set forth.

2. The herein described thermostat, the same consisting of a casing, astrip of expansible material secured at its ends to said casing andforming an angle between them, a lever pivoted to the casing, a springextending over said angle with one end bent sharply back and secured tothe strip near its angle, and connections between its otherfendand thelever, as and for the purpose set forth.

3. The combination with an incubator having a Ventilating register; of athermostat comprising a casing within said incubator, a strip ofexpansible material secured at its ends to said casing and forming anangle between them, a spring extending over said angle and secured atone end to the strip near its angle, and connections between its otherend and the register, as and for the purpose set forth.

4. In a thermostat, an expansible strip secured at its ends to a baseand bent upward at its center in an angle, a transverse row ofperforations being here provided, the strip each side of said. anglebeing wider and its edges bent down; in combination with connectionsbetween such angle and the work to be done, as and for the purpose setforth.

5. In a thermostat, an expansible strip having an upward angle at itscenter and a transverse series of perforations near each end outside ofwhich the ends are bent up and then out to form a foot; combined withconnections betweensaid angle and the work to be done, a base, blocksthereon upon which said feet rest, and screws throughthe ends of thestrips into the blocks, as and for the purpose set forth.

6. In a thermostat, an expansible strip bent into an obtuse angle at itscenter and there provided with a transverse row of perforations, itsends being bent up to form feet, series of transverse perforations justinside said feet, the body of the strip between said center and endperforations being wider and its edges bent down; combined with a base,blocks on the same to which said feet are secured, and connectionsbetween said angle and the work to be done, as and for the purpose setforth.

7. In a thermostat, the combination with a base having grooves; of anexpansible strip having an upwardly-bent angle at its center anddepending side Iianges extending from too near said angle to near itsends, the outer IIO

